Kobayashi NS, et al. - Physicians intended to examine whether apical opacities on computed tomography (CT) were associated with the occurrence of primary spontaneous pneumothorax (PSP) in young male patients. They found a significant association of apical opacities on CT with PSP in young male patients. Histopathologically, these apical opacities corresponded to fibrotic pleural thickening with subpleural alveolar collapse.